Step 1

Preheat the oven to 350°F. Grease a 9x13-inch baking pan.

Step 2

In a medium bowl, whisk together the flour, baking soda, cinnamon, and salt. Set aside.

Step 3

In a large bowl, whisk together the oil, granulated sugar, brown sugar, eggs, and vanilla until smooth.

Step 4

Gradually stir the dry ingredients into the wet ingredients until just combined. Fold in the grated carrots, nuts, and raisins (if using).

Step 5

Pour the batter into the prepared pan and spread evenly. Bake for 35-45 minutes, until a toothpick inserted into the center comes out clean. Let cool completely in the pan on a wire rack.

Step 6

Make the cream cheese frosting. In a large bowl, beat the butter and cream cheese with an electric mixer on medium speed until smooth and creamy, about 2 minutes.

Step 7

Beat the vanilla and salt into the butter and cream cheese mixture. Gradually add the powdered sugar, mixing on low until combined. Increase the speed to medium-high and beat until fluffy, 1-2 minutes.

Step 8

Spread the frosting evenly over the cooled cake. If desired, sprinkle chopped nuts on top.

Step 9

Refrigerate for at least 30 minutes before slicing and serving to allow the frosting to set.